From: Wei Chen <Wei.Chen@arm.com>
To: Stefano Stabellini <sstabellini@kernel.org>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"julien@xen.org" <julien@xen.org>,
Bertrand Marquis <Bertrand.Marquis@arm.com>
Subject: RE: [PATCH 31/37] xen/arm: introduce a helper to parse device tree NUMA distance map
Date: Fri, 24 Sep 2021 05:23:45 +0000 [thread overview]
Message-ID: <DB9PR08MB6857DE08F7A14D887CD6DBC99EA49@DB9PR08MB6857.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <alpine.DEB.2.21.2109231958250.17979@sstabellini-ThinkPad-T480s>
Hi Stefano,
> -----Original Message-----
> From: Stefano Stabellini <sstabellini@kernel.org>
> Sent: 2021年9月24日 11:05
> To: Wei Chen <Wei.Chen@arm.com>
> Cc: xen-devel@lists.xenproject.org; sstabellini@kernel.org; julien@xen.org;
> Bertrand Marquis <Bertrand.Marquis@arm.com>
> Subject: Re: [PATCH 31/37] xen/arm: introduce a helper to parse device
> tree NUMA distance map
>
> On Thu, 23 Sep 2021, Wei Chen wrote:
> > A NUMA aware device tree will provide a "distance-map" node to
> > describe distance between any two nodes. This patch introduce a
> > new helper to parse this distance map.
> >
> > Signed-off-by: Wei Chen <wei.chen@arm.com>
> > ---
> > xen/arch/arm/numa_device_tree.c | 106 ++++++++++++++++++++++++++++++++
> > 1 file changed, 106 insertions(+)
> >
> > diff --git a/xen/arch/arm/numa_device_tree.c
> b/xen/arch/arm/numa_device_tree.c
> > index 7918a397fa..e7fa84df4c 100644
> > --- a/xen/arch/arm/numa_device_tree.c
> > +++ b/xen/arch/arm/numa_device_tree.c
> > @@ -136,3 +136,109 @@ static int __init fdt_parse_numa_memory_node(const
> void *fdt, int node,
> >
> > return 0;
> > }
> > +
> > +
> > +/* Parse NUMA distance map v1 */
> > +static int __init fdt_parse_numa_distance_map_v1(const void *fdt, int
> node)
> > +{
> > + const struct fdt_property *prop;
> > + const __be32 *matrix;
> > + uint32_t entry_count;
> > + int len, i;
> > +
> > + printk(XENLOG_INFO "NUMA: parsing numa-distance-map\n");
> > +
> > + prop = fdt_get_property(fdt, node, "distance-matrix", &len);
> > + if ( !prop )
> > + {
> > + printk(XENLOG_WARNING
> > + "NUMA: No distance-matrix property in distance-map\n");
>
> I haven't seen where this is called from yet but make sure to print an
> error here only if NUMA info is actually expected and required, not on
> regular non-NUMA boots on non-NUMA machines.
>
Only users enable NUMA option and numa_off is false, then Xen can run into
this function (this check is in numa_init). So non-NUMA machines will not
reach here.
>
> > + return -EINVAL;
> > + }
> > +
> > + if ( len % sizeof(uint32_t) != 0 )
> > + {
> > + printk(XENLOG_WARNING
> > + "distance-matrix in node is not a multiple of u32\n");
> > + return -EINVAL;
> > + }
> > +
> > + entry_count = len / sizeof(uint32_t);
> > + if ( entry_count == 0 )
> > + {
> > + printk(XENLOG_WARNING "NUMA: Invalid distance-matrix\n");
> > +
> > + return -EINVAL;
> > + }
> > +
> > + matrix = (const __be32 *)prop->data;
> > + for ( i = 0; i + 2 < entry_count; i += 3 )
> > + {
> > + uint32_t from, to, distance, opposite;
> > +
> > + from = dt_next_cell(1, &matrix);
> > + to = dt_next_cell(1, &matrix);
> > + distance = dt_next_cell(1, &matrix);
> > + if ( (from == to && distance != NUMA_LOCAL_DISTANCE) ||
> > + (from != to && distance <= NUMA_LOCAL_DISTANCE) )
> > + {
> > + printk(XENLOG_WARNING
> > + "NUMA: Invalid distance: NODE#%u->NODE#%u:%u\n",
> > + from, to, distance);
> > + return -EINVAL;
> > + }
> > +
> > + printk(XENLOG_INFO "NUMA: distance: NODE#%u->NODE#%u:%u\n",
> > + from, to, distance);
> > +
> > + /* Get opposite way distance */
> > + opposite = __node_distance(from, to);
>
> This is not checking for the opposite node distance but...
>
Ah, yes, it's a mistake. It should be __node_distance(to, from);
>
> > + if ( opposite == 0 )
> > + {
> > + /* Bi-directions are not set, set both */
> > + numa_set_distance(from, to, distance);
> > + numa_set_distance(to, from, distance);
>
> ...since you set both directions here at once then it is OK. You are
> checking if this direction has already been set which is correct I
> think. But the comment "Get opposite way distance" and the variable name
> "opposite" are wrong.
>
My above mistake make this mis-understanding:
I want to check the opposite way distance is set or not.
If opposite way distance is not set, I will set both way here.
So I will change " opposite = __node_distance(from, to);" to
" opposite = __node_distance(to, from);". And keep the comment.
How do you think about it?
>
> > + }
> > + else
> > + {
> > + /*
> > + * Opposite way distance has been set to a different value.
> > + * It may be a firmware device tree bug?
> > + */
> > + if ( opposite != distance )
> > + {
> > + /*
> > + * In device tree NUMA distance-matrix binding:
> > + *
> https://www.kernel.org/doc/Documentation/devicetree/bindings/numa.txt
> > + * There is a notes mentions:
> > + * "Each entry represents distance from first node to
> > + * second node. The distances are equal in either
> > + * direction."
> > + *
> > + * That means device tree doesn't permit this case.
> > + * But in ACPI spec, it cares to specifically permit
> this
> > + * case:
> > + * "Except for the relative distance from a System
> Locality
> > + * to itself, each relative distance is stored twice
> in the
> > + * matrix. This provides the capability to describe
> the
> > + * scenario where the relative distances for the two
> > + * directions between System Localities is different."
> > + *
> > + * That means a real machine allows such NUMA
> configuration.
> > + * So, place a WARNING here to notice system
> administrators,
> > + * is it the specail case that they hijack the device
> tree
> > + * to support their rare machines?
> > + */
> > + printk(XENLOG_WARNING
> > + "Un-matched bi-direction! NODE#%u->NODE#%u:%u,
> NODE#%u->NODE#%u:%u\n",
> > + from, to, distance, to, from, opposite);
>
> PRIu32
Yes.
>
>
> > + }
> > +
> > + /* Opposite way distance has been set, just set this way */
> > + numa_set_distance(from, to, distance);
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > --
> > 2.25.1
> >
next prev parent reply other threads:[~2021-09-24 5:24 UTC|newest]
Thread overview: 192+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-23 12:01 [PATCH 00/37] Add device tree based NUMA support to Arm Wei Chen
2021-09-23 12:02 ` [PATCH 01/37] xen/arm: Print a 64-bit number in hex from early uart Wei Chen
2021-09-23 12:02 ` [PATCH 02/37] xen: introduce a Kconfig option to configure NUMA nodes number Wei Chen
2021-09-23 23:45 ` Stefano Stabellini
2021-09-24 1:24 ` Wei Chen
2021-09-24 8:55 ` Jan Beulich
2021-09-24 10:33 ` Wei Chen
2021-09-24 10:47 ` Jan Beulich
2021-09-23 12:02 ` [PATCH 03/37] xen/x86: Initialize memnodemapsize while faking NUMA node Wei Chen
2021-09-24 8:57 ` Jan Beulich
2021-09-24 10:34 ` Wei Chen
2021-09-23 12:02 ` [PATCH 04/37] xen: introduce an arch helper for default dma zone status Wei Chen
2021-09-23 23:55 ` Stefano Stabellini
2021-09-24 1:50 ` Wei Chen
2022-01-17 16:10 ` Jan Beulich
2022-01-18 7:51 ` Wei Chen
2022-01-18 8:16 ` Jan Beulich
2022-01-18 9:20 ` Wei Chen
2022-01-18 14:16 ` Jan Beulich
2022-01-19 2:49 ` Wei Chen
2022-01-19 7:50 ` Jan Beulich
2022-01-19 8:33 ` Wei Chen
2021-09-23 12:02 ` [PATCH 05/37] xen: decouple NUMA from ACPI in Kconfig Wei Chen
2021-09-23 12:02 ` [PATCH 06/37] xen/arm: use !CONFIG_NUMA to keep fake NUMA API Wei Chen
2021-09-24 0:05 ` Stefano Stabellini
2021-09-24 10:21 ` Wei Chen
2021-09-23 12:02 ` [PATCH 07/37] xen/x86: use paddr_t for addresses in NUMA node structure Wei Chen
2021-09-24 0:11 ` Stefano Stabellini
2021-09-24 0:13 ` Stefano Stabellini
2021-09-24 3:00 ` Wei Chen
2022-01-18 15:22 ` Jan Beulich
2022-01-19 6:33 ` Wei Chen
2022-01-19 7:55 ` Jan Beulich
2022-01-19 8:36 ` Wei Chen
2021-09-23 12:02 ` [PATCH 08/37] xen/x86: add detection of discontinous node memory range Wei Chen
2021-09-24 0:25 ` Stefano Stabellini
2021-09-24 4:28 ` Wei Chen
2021-09-24 19:52 ` Stefano Stabellini
2021-09-26 10:11 ` Wei Chen
2021-09-27 3:13 ` Stefano Stabellini
2021-09-27 5:05 ` Stefano Stabellini
2021-09-27 9:50 ` Wei Chen
2021-09-27 17:19 ` Stefano Stabellini
2021-09-28 4:41 ` Wei Chen
2021-09-28 4:59 ` Stefano Stabellini
2022-01-18 16:13 ` Jan Beulich
2022-01-19 7:33 ` Wei Chen
2022-01-19 8:01 ` Jan Beulich
2022-01-19 8:24 ` Wei Chen
2021-09-23 12:02 ` [PATCH 09/37] xen/x86: introduce two helpers to access memory hotplug end Wei Chen
2021-09-24 0:29 ` Stefano Stabellini
2021-09-24 4:21 ` Wei Chen
2022-01-24 16:24 ` Jan Beulich
2022-01-26 7:53 ` Wei Chen
2021-09-23 12:02 ` [PATCH 10/37] xen/x86: use helpers to access/update mem_hotplug Wei Chen
2021-09-24 0:31 ` Stefano Stabellini
2021-09-24 4:29 ` Wei Chen
2022-01-24 16:29 ` Jan Beulich
2022-01-26 7:58 ` Wei Chen
2021-09-23 12:02 ` [PATCH 11/37] xen/x86: abstract neutral code from acpi_numa_memory_affinity_init Wei Chen
2021-09-24 0:38 ` Stefano Stabellini
2022-01-24 16:50 ` Jan Beulich
2022-01-26 10:39 ` Wei Chen
2021-09-23 12:02 ` [PATCH 12/37] xen/x86: decouple nodes_cover_memory from E820 map Wei Chen
2021-09-24 0:39 ` Stefano Stabellini
2022-01-24 16:59 ` Jan Beulich
2022-01-27 8:03 ` Wei Chen
2022-01-27 8:08 ` Jan Beulich
2022-01-27 9:03 ` Wei Chen
2022-01-27 9:22 ` Jan Beulich
2022-01-27 9:27 ` Wei Chen
2021-09-23 12:02 ` [PATCH 13/37] xen/x86: decouple processor_nodes_parsed from acpi numa functions Wei Chen
2021-09-24 0:40 ` Stefano Stabellini
2022-01-25 9:49 ` Jan Beulich
2022-01-27 8:06 ` Wei Chen
2021-09-23 12:02 ` [PATCH 14/37] xen/x86: use name fw_numa to replace acpi_numa Wei Chen
2021-09-24 0:40 ` Stefano Stabellini
2022-01-25 10:12 ` Jan Beulich
2022-01-27 8:09 ` Wei Chen
2021-09-23 12:02 ` [PATCH 15/37] xen/x86: rename acpi_scan_nodes to numa_scan_nodes Wei Chen
2021-09-24 0:40 ` Stefano Stabellini
2022-01-25 10:17 ` Jan Beulich
2022-01-27 8:14 ` Wei Chen
2021-09-23 12:02 ` [PATCH 16/37] xen/x86: export srat_bad to external Wei Chen
2021-09-24 0:41 ` Stefano Stabellini
2022-01-25 10:22 ` Jan Beulich
2022-01-27 8:35 ` Wei Chen
2022-01-27 8:37 ` Jan Beulich
2022-01-27 8:47 ` Wei Chen
2021-09-23 12:02 ` [PATCH 17/37] xen/x86: use CONFIG_NUMA to gate numa_scan_nodes Wei Chen
2021-09-24 0:41 ` Stefano Stabellini
2022-01-25 10:26 ` Jan Beulich
2022-01-27 8:37 ` Wei Chen
2021-09-23 12:02 ` [PATCH 18/37] xen: move NUMA common code from x86 to common Wei Chen
2021-09-23 12:02 ` [PATCH 19/37] xen/x86: promote VIRTUAL_BUG_ON to ASSERT in Wei Chen
2022-01-17 16:21 ` Jan Beulich
2022-01-18 7:52 ` Wei Chen
2021-09-23 12:02 ` [PATCH 20/37] xen: introduce CONFIG_EFI to stub API for non-EFI architecture Wei Chen
2021-09-24 1:15 ` Stefano Stabellini
2021-09-24 4:34 ` Wei Chen
2021-09-24 7:58 ` Jan Beulich
2021-09-24 10:31 ` Wei Chen
2021-09-24 10:49 ` Jan Beulich
2021-09-26 10:25 ` Wei Chen
2021-09-27 10:28 ` Wei Chen
2021-09-28 0:59 ` Stefano Stabellini
2021-09-28 4:16 ` Wei Chen
2021-09-28 5:01 ` Stefano Stabellini
2021-09-28 8:02 ` Jan Beulich
2021-10-03 23:28 ` Wei Chen
2022-01-25 10:34 ` Jan Beulich
2022-01-27 8:44 ` Wei Chen
2022-01-27 8:51 ` Wei Chen
2022-01-27 9:00 ` Jan Beulich
2022-01-27 9:09 ` Wei Chen
2022-01-27 9:16 ` Jan Beulich
2022-01-27 9:25 ` Wei Chen
2022-01-27 9:27 ` Jan Beulich
2022-01-27 10:00 ` Julien Grall
2022-01-28 4:35 ` Wei Chen
2021-09-23 12:02 ` [PATCH 21/37] xen/arm: Keep memory nodes in dtb for NUMA when boot from EFI Wei Chen
2021-09-24 1:23 ` Stefano Stabellini
2021-09-24 4:36 ` Wei Chen
2022-01-25 10:38 ` Jan Beulich
2022-01-27 8:45 ` Wei Chen
2021-09-23 12:02 ` [PATCH 22/37] xen/arm: use NR_MEM_BANKS to override default NR_NODE_MEMBLKS Wei Chen
2021-09-24 1:34 ` Stefano Stabellini
2021-09-26 13:13 ` Wei Chen
2021-09-27 3:25 ` Stefano Stabellini
2021-09-27 4:18 ` Wei Chen
2021-09-27 4:59 ` Stefano Stabellini
2021-09-27 6:25 ` Julien Grall
2021-09-27 6:46 ` Wei Chen
2021-09-27 6:53 ` Wei Chen
2021-09-27 7:35 ` Julien Grall
2021-09-27 10:21 ` Wei Chen
2021-09-27 10:39 ` Julien Grall
2021-09-27 16:58 ` Stefano Stabellini
2021-09-28 2:57 ` Wei Chen
2021-09-23 12:02 ` [PATCH 23/37] xen/arm: implement node distance helpers for Arm Wei Chen
2021-09-24 1:46 ` Stefano Stabellini
2021-09-24 4:41 ` Wei Chen
2021-09-24 19:36 ` Stefano Stabellini
2021-09-26 10:15 ` Wei Chen
2021-09-23 12:02 ` [PATCH 24/37] xen/arm: implement two arch helpers to get memory map info Wei Chen
2021-09-24 2:06 ` Stefano Stabellini
2021-09-24 4:42 ` Wei Chen
2021-09-23 12:02 ` [PATCH 25/37] xen/arm: implement bad_srat for Arm NUMA initialization Wei Chen
2021-09-24 2:09 ` Stefano Stabellini
2021-09-24 4:45 ` Wei Chen
2021-09-24 8:07 ` Jan Beulich
2021-09-24 19:33 ` Stefano Stabellini
2021-09-23 12:02 ` [PATCH 26/37] xen/arm: build NUMA cpu_to_node map in dt_smp_init_cpus Wei Chen
2021-09-24 2:26 ` Stefano Stabellini
2021-09-24 4:25 ` Wei Chen
2021-09-23 12:02 ` [PATCH 27/37] xen/arm: Add boot and secondary CPU to NUMA system Wei Chen
2021-09-23 12:02 ` [PATCH 28/37] xen/arm: stub memory hotplug access helpers for Arm Wei Chen
2021-09-24 2:33 ` Stefano Stabellini
2021-09-24 4:26 ` Wei Chen
2021-09-23 12:02 ` [PATCH 29/37] xen/arm: introduce a helper to parse device tree processor node Wei Chen
2021-09-24 2:44 ` Stefano Stabellini
2021-09-24 4:46 ` Wei Chen
2021-09-23 12:02 ` [PATCH 30/37] xen/arm: introduce a helper to parse device tree memory node Wei Chen
2021-09-24 3:05 ` Stefano Stabellini
2021-09-24 7:54 ` Wei Chen
2021-09-23 12:02 ` [PATCH 31/37] xen/arm: introduce a helper to parse device tree NUMA distance map Wei Chen
2021-09-24 3:05 ` Stefano Stabellini
2021-09-24 5:23 ` Wei Chen [this message]
2021-09-23 12:02 ` [PATCH 32/37] xen/arm: unified entry to parse all NUMA data from device tree Wei Chen
2021-09-24 3:16 ` Stefano Stabellini
2021-09-24 7:58 ` Wei Chen
2021-09-24 19:42 ` Stefano Stabellini
2021-09-23 12:02 ` [PATCH 33/37] xen/arm: keep guest still be NUMA unware Wei Chen
2021-09-24 3:19 ` Stefano Stabellini
2021-09-24 10:23 ` Wei Chen
2021-09-23 12:02 ` [PATCH 34/37] xen/arm: enable device tree based NUMA in system init Wei Chen
2021-09-24 3:28 ` Stefano Stabellini
2021-09-24 9:52 ` Wei Chen
2021-09-23 12:02 ` [PATCH 35/37] xen/arm: use CONFIG_NUMA to gate node_online_map in smpboot Wei Chen
2021-09-23 12:02 ` [PATCH 36/37] xen/arm: Provide Kconfig options for Arm to enable NUMA Wei Chen
2021-09-24 3:31 ` Stefano Stabellini
2021-09-24 10:13 ` Wei Chen
2021-09-24 19:39 ` Stefano Stabellini
2021-09-27 8:33 ` Jan Beulich
2021-09-27 8:45 ` Julien Grall
2021-09-27 9:17 ` Jan Beulich
2021-09-27 17:17 ` Stefano Stabellini
2021-09-28 2:59 ` Wei Chen
2021-09-28 3:30 ` Stefano Stabellini
2021-09-24 10:25 ` Jan Beulich
2021-09-24 10:37 ` Wei Chen
2021-09-23 12:02 ` [PATCH 37/37] docs: update numa command line to support Arm Wei Chen
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